This invention relates generally to copying machines of the type in which the original or pattern is projected in a strip-like manner on an image recording support by means of a pattern scanning unit movable in guiding grooves of an objective housing along the pattern and including a plurality of scanning lens plates which for the sake of uniform projection of the composed image resulting from the subsequent or overlapping partial image projections cooperate with a plurality of diaphragms such as, for example, aperture diaphragm and/or image field diaphragm or separating diaphragm preventing overlapping of respective strip-like partial images. In particular, this invention relates to the pattern scanning unit for such copying machines.
The pattern scanning devices for copying machines of the aforedescribed type are described for example in the German Pat. No. 1,203,115 and in the German published patent application No. 2,421,661. The disadvantage of such prior art scanning devices, however, is in a relatively complicated production and in the sensitivity to manufacturing inaccuracies or to changes resulting from mechanical or thermal stresses.